The legendary climb comes at the end of a 242.5 stage from Givors and should see a shake out in the race for the yellow jersey.

Contador, a two time Tour de France champion, currently sits in third overall, 2:45 behind race leader Chris Froome. However, with five riders between second place and fifth separated by less than 35 seconds, the race could boil down to a tactical war of attrition, with Contador and Bauke Mollema each joined by a teammate each inside the top five overall.

Danger man Nairo Quintana sits over five minutes down in GC but could also play a significant part.

"Tomorrow will be a hard stage because the number of kilometers, and because the Mont Ventoux is a special mountain," Contador said at the end of stage 14 to Lyon, which saw Omega Pharma-Quick-Step pick up its fourth stage win of the race.

Contador and the Tour last raced up the Ventoux in 2009 towards the end of that year's race. By that stage the Spaniard was in control and only had to mark his closet rivals to secure his second Tour win.

This time around he may choose to be more aggressive but legs depending, he may also need to limit his losses if Froome is still in the shape he demonstrated in the Pyrenees.

"I would divide the climb into two parts," Contador said. "The first is about percentage and gradient, and is covered with vegetation, but the second is windy, and there's usually a headwind. I guess in tomorrow's stage there will be a break until the start of the climb and many movements in the race, by Movistar, for example, from the beginning. Will have to see how the legs go and what tactics are employed by other teams".

"The first part is very hard and the last 5 kilometres are easier if you follow wheels, but it's a climb where if you have a bad day you can lose many minutes. Tomorrow I think there will be many attacks and hope the legs work well."

The gruelling slopes of Ventoux may not decide the Tour's winner but they will give a clearer indication of Contador's form and whether he has improved since the Pyrenees. Froome has had the measure of the Spaniard for most of the season, but Contador has pointed to the fact that he typically improves over three weeks, as he demonstrated after the second rest day in last year's Vuelta.

Alliances may also play a part on Ventoux.

"There will be two races, one for the stage and another for the general classification, but I don't expect alliances, unless interests coincide.

"Everyone does his race, although there may be circumstances when you can benefit and work together with other riders, but I don't see alliances in advance," he finished.